Decompositions of metastable [C6H12O]+ ions with the oxygen on the third carbon: Ring-size preferences in [CnH2nO]+˙ ions

The isomerizations preceding the metastable decompositions in the mass spectrometer of a number of [C₆H₁₂O]⁺˙ ions with the oxygen on the third carbon are characterized utilizing deuterium labeling. Hydrogens are transferred in these ions by three-, five- and six-membered ring rearrangements, with propensities determined by features of the individual reactions. Three-membered ring hydrogen transfers between α and β-carbons are preferred to all five-membered ring hydrogen transfers. However, six-membered ring hydrogen transfers take place to the apparent exclusion of three-membered ring hydrogen transfers to enol carbons when the products are of comparable stability. The low-energy [C₆H₁₂O]⁺˙ isomerizations characterized are predictable from the behavior of their lower homologs. It is concluded that the determinants of these reactions are the same as those of other highly reactive organic intermediates.     

Classification of chromatographic data using multidimensional polynomials

Summary A pattern recognition methodology has been developed for analysis of chromatographic data. The method uses a new class of multidimensional orthogonal polynomials developed by Cohen in conjunction with a supervised learning technique. The method is applicable to any chromatographic data for which classification into two or more categories is desired. The algorithm analyzes both elution times and peak areas. An application is shown for the analysis of organic acids in ascitic fluid obtained from patients with liver disorders. Classification of these patients for presence or absence of bacterial infection shows over ninety percent correct classification.     

[Sm(NO3)3(TPTZ)(H2O)]·2H2O [TPTZ is 2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine]

The title compound, aqua­tris­(nitrato)[2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine]samarium dihydrate, [Sm(NO₃)₃­(C₁₈H₁₂N₆)­(H₂O)]·­2H₂O, was prepared from Sm(NO₃)₃·6H₂O and 2,4,6‐tris(2‐pyridyl)‐1,3,5‐triazine. The metal atom is ten‐coordinate being bonded to the terdentate TPTZ ligand, three bidentate nitrates and a water mol­ecule.     

An INDO study of the hyperfine coupling constants and equilibrium geometries of some tetra-atomic radicals

Equilibrium geometries and isotropic hyperfine coupling constants have been estimated for the series of radicals CH _n F_3-n , CH _n Cl_3-n , CCl _n F_3-n and S₁H _n F_3-n using the INDO method. The theoretical hyperfine splittings agree well with experimental values including the unusually large proton splittings of 34·6 G and 89·9 G recently reported for SiH₂F and SiHF₂.     

Non-linear response of liquid crystal spatial light modulators

This technical note outlines the results of a series of experiments performed on two spatial light modulators. The two modulators were a Hughes Corporation LCLV and an optically-addressed ferroelectric liquid crystal SLM fabricated by the University of Colorado at Boulder and Displaytech. These experiments were performed to determine the modulated response of the read beam as a function of the write light intensity.     

Synthesis of cross-conjugated polyketones by the crossed-aldol condensation of cyclic ketones with aromatic dialdehydes

Insoluble cross-conjugated polyketones were prepared from terephthalaldehyde and a variety of cycloaliphatic ketones by the crossed-aldol condensation. Elemental analyses and infrared spectra suggest that the polymeric aldol intermediates were not completely dehydrated. Evidence is also presented that suggests conjugate addition of the base to the α,β-unsaturated ketone may occur. Soluble cross-conjugated polyketones were prepared from terephthalaldehyde and 2-indanone, which contains no beta hydrogens, and from cycloaliphatic ketones and 1,2-bis(4-formylphenoxy)ethane, a dialdehyde containing isolated aldehyde groups. It is proposed, therefore, that the lack of solubility in the terephthalaldehyde-based polyketones arises from crosslinking via enolate anions formed at the beta position of the cyclic ketones, which are delocalized through the carbonyl groups of neighboring backbone repeating units. © 1995 John Wiley & Sons, Inc.